Weed interference at the beginning of the wheat cycle can compromise crop productivity by up to 80%, depending on which weeds are present in the area and the level of infestation. Furthermore, over the years, the difficulty in controlling post-emergence weeds has been increasing, due to the increase in infestations and the resistance of some weeds to herbicides. In view of this, the use of pre-emergent herbicides as a control strategy has proven to be an effective tool, in addition to providing a "clean" emergence of the crop, facilitating the management of weeds in post-emergence.
Pre-emergent herbicides: how they work and how they benefit
Pre-emergent herbicides are chemical products applied to the soil before weeds and wheat germinate, using a plant/apply or apply/plant application. The main function of these herbicides is to create a chemical barrier that acts directly on the surface layer of the soil, preventing weed seeds from germinating or seedlings in the early stages of development from growing healthily. This is because they interfere with the cell division process, which inhibits the emergence of weeds, and their action is directed at invasive species without directly affecting the wheat, when the correct herbicide is used.
This control method is extremely important because it acts preventively, preventing weeds from competing with wheat from the beginning of its development. Competition for light, nutrients and water can significantly harm crop productivity and, in some cases, weed interference can reduce wheat productivity by up to 80%, which highlights the importance of strategies such as the use of pre-emergent herbicides.
Criteria for choosing a herbicide
1. Control spectrum
The choice of herbicide should consider the main weed species present in the area. In the case of wheat, grasses such as ryegrass (Lolium multiflorum) and other species are common and can be controlled by herbicides such as Trifluralina Nortox Gold (https://www.3tentos.online/trifluralina-nortox-gold/p). This product is a selective pre-emergent herbicide, belonging to the dinitroaniline family, with action in the soil and absorption by the roots and coleoptiles of germinating plants. Its mode of action prevents cell division, inhibiting seedling growth and effectively controlling the emergence of grasses and other sensitive weeds, ensuring a wheat crop with less competitive interference.
2. Persistence in the soil
Herbicides with greater residual action in the soil provide longer-lasting weed control, reducing the need for reapplication. However, the time the herbicide molecule remains in the soil must be taken into account to avoid harmful effects on subsequent crops, such as soybeans.
Benefits of the correct use of pre-emergent herbicides
? Reduction in initial competition, allowing for better wheat development;
? Reduction in the need for post-emergent herbicides, reducing costs and environmental impacts;
? Efficient resistance management, avoiding the selection of weeds tolerant to post-emergent herbicides;
? Greater flexibility in agricultural management, favoring crop rotation and diversification of control strategies.
The selection and proper use of pre-emergent herbicides are essential to ensure the success of wheat crops. In addition to providing effective weed control, this practice results in higher productivity, lower costs with post-emergent products and contributes to the sustainability of the crop. For additional information, contact a 3tentos consultant.
Text written by Gabriela Martins and Diego Outeiro, members of AGR Jr. Consultoria Agronômica, a Junior Company of the Agronomy Course at UFSM Campus Frederico Westphalen, under the guidance of Professor Gizelli Moiano de Paula.
BIBLIOGRAPHICAL REFERENCES
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